Suction moulds



V, E. MAJANLAHTI Sept. 13, 1960 i SUCTION MOULDS 4 Sheets-Sheet 1 Filed Sept. '7, 1956 v. E; MAJANLAHTI Sept. 13, 1.960

SUCTION MOULDS 4 Sheetsr-Sheet 2 Filed Sept. 7, 1956 IN VEN TO R 1 f. MfimuL/mr/ Sept. 13 1960 Filed Sept 7, 1956 v. E. MAJANLAHTI 2,95 ,317

SUCTION MOULDS 4 Sheets-Sheet 3 INVNTOR V E'. Mnmwmnn Sept. 13, 1960 v, E. MAJANLAHTl- SUCTION MOULDS 4 Sheets-Sheet 4 Filed Sept 7, 1956 I/VVENTOR V E. MIqJ/INL mm SUCTION MOULDS Vaino E. Majanlahti, St. Laurent, Quebec, Klanada, as-

signor to Paper Machinery Limited, Montreal, Quebec, Canada Filed 'Sept. 7, 1956, Ser. No. 608,618'

8 Claims (Cl. 162-457) This invention relates to improvements in suction moulds and particularly to suction moulds used for drying groundwood or chemical pulp.

Earlier suction mould have generally been made of cast iron design with simple end drainage for narrow working widths. As'increased capacities were required, the working width was increased accordingly, and a central drainage suction mould was designed, passages from the center of the drum to the valve serving to empty the complete width of the cylinder'mould. The reason for the central drainage was mainly to deter water splashing back from the cells onto: the sheet under the couch roll. The-water in thecentral passages would notvsplash directly back onto the sheet.

In many cases, the cast iron construction didnot prove satisfactory due-"to the" corrosive conditions existent in some pulp and paper mills.- Consequently, the necessity arose for the. development "of astainless steel-design; It wasthen found more feasible andeconorni'cal to make the mould in fabricated'stainless steel. designs rather than as castings. For wideworking widths, the centralpassages were made in the form of pipes.- This design; however, has certain disadvantages. The-pipeshad. to be largeenough to empty'the cells over the entire-width of the machine; T hesize of thepipes led to a limitation of the number of pipes that could beinstalled, thus limiting the number of separate sections into'which'the cylinder could be divided. Normally, one pipe-would empty about five to seven oreven'up to nine cells; Am other drawback to the central drainage design was. that the flowof water from the portionof-the cylinder adja: cent to the valve is actually reversed as'it. enters into the pipes at their connection with the central: drainage section of the machine. This reversal of water fiow-furthe: added to the frictionlosses in themachinen The present inventioni is intended tea-overcome the many objections in past designs andvconsists essentially in providing direct end drainage of the cells at al-rnaximum diameter, and-.includes the :provision ofan annular plate dividing the cells radially from the valveface of the machine to. a point approximately halfway; across the working width of'the cylinder. The.dr-ainagefrom the halfof the cylinder" adjacent the valveof the machine being direct into the suction-box. through theiouter. radial halfof the cells while the drainage from the half: of the cylinder remote from thevalve of the machine being direct into the suction box through the inner radialv half ofthe cells. The water: draining. from. each half-of the width ofthe cylinder is therefore kept separate asitflows directly from the cells" into. the suction box. The: water flow from'each longitudinal half of the'cylinderfollows a straight: path 'to" the: suction box through theva'ctualflcells themselves, at the periphery; of -the mamnerso that "the valve. controlling the discharge of a water from that cells can be of maximum diameter which inturn allowssfor a-maximummumber. of separate cellsin thecyl-inder.

nited States Patent from a large number of individual cells into the suction box of the machine.

A further object of the'invention is to provide a suction mould in which the water from each longitudinal half of each cell is'discharged separately from the cell directly into the suction box of the machine.

A further object of the invention is to provide a valve between the cylinder and the suction box of the machine which controls the discharge end of the individual cells of-th'e cylinder andwhosediameter is limited only by the circumferential limitations of the suction box and cylinder, thus increasing the time available for emptying The object of the invention is. therefore to. provide a V suction mould in which the water is discharged directly the cells.

A further object of the invention is to provide a maximum ofperipheral cells in the suction mould cylinder in order to improve the uniformity of-operation of the machine.

A further object ofthe invention is to provide an improved streamlined flow of the filtrate, thus reducing the hydraulic friction. and allow faster emptying of the cells.

A further object of the'invention is to reduce the tend ency for water tov splashback on the formed sheet at the couch roll, thus permitting higher speeds of operation.

A further object of the invention is to simplify the construction and consequently the cost of the machine.

These and other objects will be apparent from the following; specification and the drawings forming a part thereof in which:

Fig; 1 is a longitudinal vertical section of a suction mould incorporating my improved design and showing a pair ofcells in direct connection with the suction box for unobstructed end drainage.

Fig. 2. is anend view of the suctionv mould looking onthe suctionbox end.

Fig. 3 is a vertical section on theline 3-3 *of..Fig..1 showing the divisions of the suction box and. thevalve openings which communicate with the cylinder cells.-

7 Fig. 4- is a-vertical section on 'theline 4-4 of- Fig; 1 showing the valve seating rings and the discharge end of the cells of the cylinder,

Fig.- 5 is a vertical section on the line 55 of Fig, 1 showing the internalstructure of the cylinder supporting the inner peripheral surface of the cylinder cells,

Fig. 6- is an enlargedpartial longitudinal section showing. in detail thevalvebetweenthe cylinder cells-and the suction box.

Fig. 7 is a partial end view on the line 7-7 of Fig. 6 showing the discharge openings of the cylinder-cells;

Referring to the drawings, the suction mould 5. of the-present invention is fabricated from steel plate in' order to facilitate the manufacture of machines of maximum diameter and width to meet the present day trend; The suction mould 5 is made in three main sections, a suction box section 6, an outer end bearing section'7 and the cylinder section 8.

The cylinder section 8 comprises an outer perforated shell. 9, aninnershell 10 andatubular'support shell 11. The shells 9, land 11 are all Welded to the end plates 12 and. 13,. the shells 10 and 11 being located between the end plates while the outer shell 9 projects beyond the end plates 12 and 13 fora short distance. The tubular support-shell 11 has its ends counterbored at 14 to receive the'rings 15 which-support the stub-shafts 16 and 17, the rings 15 being; welded to the shell '11 and to the stub shafts 16 and 17' so that the .stub shafts formr-an integral part of the rotatable cylinder sections;

The outer shell has itssurface parallel with: the axis of the stubshafts 16. and 17 and is perforated at. 18-over the entire surface between the end plates 12 and 13. The inner shell 10 is slightly conical in shape withits. larger diameter abutting the end plate 13 and located relatively close to the outer shell 9. The opposite end of the inner shell is tapered inwardly at a sharp angle at 19 for a short distance before it abuts against the end plate 12. The innershelllt) is supported throughout its length, at spaced intervals, by the plate rings 20 and by the radiating end brackets 21 and 22. The end brackets 21 are welded to the shell 11, end plate 12 and portion 19 of the inner shell 10 in addition to being welded to the end plate ring 20a, while the end brackets 22 are welded to the shell 11, end plate 13, inner shell 18 and the end plate ring 20b.

The outer periphery of the cylinder section 8, between the outer shell 9 and the inner shell 10 is divided into a multiplicity of longitudinal cells 23 by the radiating dividing walls 24 which extend the full working width of the cylinder 8.

An annular plate 25 is disposed between the outer shell 9 and the inner shell 10 and extends from the suction box end of the cylinder 8 to a point approximately at the mid portion of the length of the cylinder. This annular plate lies approximately parallel with the sloping surface of the inner shell 10 and is angled at 26 opposite the angled portion 19 of the inner shell 10 to divide the discharge opening of the cells 23 into the suction box sect-ion 6, approximately in half. The annular plate 25 on its inner side forms a series of passages 27 with the inner shell 10 by means of which the water in the outer half 23a of the cells 23 can be removed without interfering with the water being removed from the inner half 23b of the cells 23.

Where the suction mould has an extra large width it may be formed with two or more plates 25 fitted in the cells 23 and spaced radially from each other and tenninating at more or less spaced intervals along the length of the cells. By this means two-thirds or perhaps threequarters of the length of the cells may be drained in separate sections, each isolated from the other thereby eliminating splash back from a greater area of the surface of the shell 9, resulting in a dryer pulp sheet leaving the surface of the cylinder.

The interior of the cylinder section 8 between the inner shell 10 and the shell 11 is entirely sealed ofI and is provided with a manhole 28 and manhole cover 29 to provide access for inspection purposes.

The discharge end of the cylinder 8 is provided with a pair of valve rings 29 and 30, the inner valve ring 29 having its outer periphery annularly in line with the edge of the tapered portion 19 of the inner shell 10. The outer valve ring 30 is located against the inner surface of the projecting end of the outer shell 9. The facing edges 29a and 30a of the rings 29 and 30 defining, with the dividing walls 24, the discharge outlets of the cells 23.

The suction box section 6 is formed of the end walls 31 and 32, an annular outer wall 33 and an inner annular Wall 34. The inner annular wall 34 is provided with a carrier ring 35 on which is mounted the bearing housing 36 carrying the main bearing 37. This bearing is held in place in its housing by the cover 38. A thrust bearing 39 is spring held in place against the cover 38 by ring 40. The spring 42 holding the thrust bearing 39 in place is adjustable on the stud 43 projecting from the end of the stub shaft 16, by the nuts 43. A cover 44 protects the bearings 37 and 39 from dirt and injury.

The end wall 32 of the suction box 6 is spaced outwardly from the end wall 12 of the cylinder section 8 and carries the inwardly projecting annular valve 45. The valve 45 is formed of a pair of annular concentric rings 46 and 47, the inner ring 46 being provided with a flange 48 and the outer ring 47 being provided with a flange 49. Both flanges 48 and 49 are in the same plane at right angles to the axis of rotation of the cylinder section 8. A seal ring 50 is secured to the flanges 48 and 49 by the bolts 50a to bear against the valve rings 29 and 30 of the cylinder section 8. The space between the two flanges 48 and 49 is divided into three arcuate ports 51,

4 V 52 and 53 by the bridges 54. The interior of the suction box 6 is divided into three compartments, by the ribs 55 radiating outwards from the annular wall 34 and following a line crossing the bridges 54 to meet with the outer annular wall 33. The compartment 56 is the vacuum compartment and is connected with a vacuum line through the flange connection 57 and has the main water discharge outlet 58. A glass covered sight hole 59 allows for inspection of the vacuum chamber at all times. The

compartment 60 is open to the atmosphere by means of the.

open elbow 61 on the outer wall 31. Air and/or water from the cells 23 is allowed to pass out through the auxiliary discharge opening 63 in compartment 62.

The end bearing section 7 has an end wall 64 supporting the ring 65 on which the bearing housing 66 is mounted. The bearing 67 journalling the stub shaft 17 is held in place within its housing 66 by the end ring cover 68.

A manhole cover 69 provides access to the space between the end walls 13 and 64 and to the manhole cover 29 leading to the interior of the cylinder section 8.

Both the suction box section 6 and the end bearing section 7 have inwardly extending annular rings 70 which together with the outwardly projecting ends of the outer shell 9 of the cylinder section 8 support the sealing strap 70a.

A trough 71 is secured to the brackets 72 on the stationary suction box section 6 and end bearing section 7 and encloses the lower half of the cylinder section 8.

The stub shaft 17 is extended at 73 and can be driven by any suitable means to rotate the cylinder section 8 at the required speed.

When the suction mould as above described is in operation, the cells 23 which are exposed to the vacuum in the vacuum chamber 56 through the port 51 will draw water through the aperture 18 from the mass of pulp forming on the outer surface of the shell 9. The water passing into the outer half 2312 of the cells 23 is drawn along the sloping surface of the inner shell 10 and through the passages 27 in a direct path to the large area port 51 where it is free to flow down to the discharge outlet 58. The curve of the outer wall 33 and the slope of the adjacent rib 55 directs the water into the discharge outlet without obstruction.

As the cells 23 are rotated with the cylinder 8 into the area of the port 52 the vacuum is broken as the chamber 60 connected with the port 52 is open to the atmosphere through the open elbow 61. The formed pulp sheet on the cylinder 8 is stripped from the cylinder as soon as the vacuum is broken, so that the cells 23 throughout the length of the cylinder are also open to the atmosphere through the apertures 18.

The end drainage from each half of the cells 23 through separate channels ensures that the water will be discharged quickly and directly without changes in direction of flow. The tapered section of each half 23a and 23b of the cells is adequate to ensure free flow of the water and the Water from the half sections 23a is carried through the pasages 27 without interfering in any way with the water flowing in the sections 23b. Should any water remain in passages 27 it will be prevented from splashing onto the pulp sheet by the annular plate 25. The wide arcuate ports 51, 52 and 53 allow a maximum of communication area between the suction box section 6 and the cylin der cells 23 whether for the application of vacuum and the discharge of water or for the breaking of the vacuum in the cells, so that at all times, the suction mould will operate at maximum efliciency for the drying of the forming pulp sheet.

The light-weight construction of the unit as a whole and the concentration of the vacuum application and water discharge at the periphery of the machine combine to provide a suction mould of great simplicity which can be of any large width to suit modern requirements while retaining the advantages of simple end drainage. Furthermore, the wide arcuate ports located near the periphery of the suction boxsection permits of a large number of individual cells to be formed under the outer shell of the cylinder which in turn allows for greater uniformity in operation. As compared with central drainage design moulds of equivalent dimensions the fluid friction is reduced as a more streamlined flow is obtained and only half the flow passes through the pasages 27.

Although in the foregoing the design and construction of a suction mould has been referred to as being used in drying groundwood or chemical pulp, it is understood that the design could be used equally eifectively for vacuurn type wash filters or thickeners in the pulp and paper industry. Further-more, although the design shows a fiat valve seat, the design would also be applicable to cylindrical or conical valve seats without departing from the spirit of the invention and the claims of the application should be so construed.

Although in the foregoing the outer shell 9 has been referred to as a perforated plate, the design would also be applicable if this were made in the form of a wound wire or other similar permeable surface.

What I claim is: 1

1. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, and an annular division plate in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box.

2. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, said inner shell having its surface tapered slightly inwards towards the suction box end, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, and an annular division plate in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length and being located parallel with the tapered surface of the inner shell to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box.

3. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, an annular division plate in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box, and a valve in said suction box controlling the application of vacuum to said cells.

4. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a 6 stationary suction box section and a stationary outer bear ing section, said cylinder section having an outer perforated shell and an inner imperforated shell, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, annular division plates in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box, inner and outer annular valve faces on the end of said cylinder section defining the outer and inner radial edges of the open ends of the cells and a ported valve face on said suction box section facing against said inner and outer valve faces and controlling the application of vacuum to said cells.

5. In a suction mould for drying pulp or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, said inner shell being tapered inwardly from the end of the cylinder adjacent the outer bearing section towards the suction box section, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, an annular division plate in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box, and a valve in said suction box controlling the application of vacuum to said cells.

6. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, said inner shell being tapered inwardly from the end of the cylinder adjacent the outer bearing section towards the suction box section, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, an annular division plate in each of said cells, said annular division plates extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages Within the passages connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box, inner and outer annular valve faces on the end of said cylinder defining the outer and inner radial edges of the open ends of the cells, and a ponted valve face on said suction box section facing against said inner and outer annular valve faces and controlling the application of vacuum to said cells.

7. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, said inner shell being tapered inwardly from the end of the cylinder adjacent the outer bearing section towards the suction box section, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their end adjacent to said suction box section, an annular division plate in each of said cells said annular division plates being located parallel with the surface of said inner shell and extending from the open end of the cells adjacent to the suction box section to. a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction :box, inner and outer annular valve faces on the end of said cylinder defining the outer and inner radial edges of the open ends of the cells, and a. ported valve face on said suction box section fiacing against said inner and outer annular valve faces and controlling the application of vacuum to said cells. I

8. In a suction mould for drying pulp, or like machine in which a cylinder section is rotatably mounted between a stationary suction box section and a stationary outer bearing section, said cylinder section having an outer perforated shell and an inner imperforated shell, said inner shell being tapered inwardly from the end of the cylinder adjacent the outer bearing section towards the suction box section, a series of radial division plates located between said inner and outer shells dividing the annular space therebetween into a multiplicity of longitudinal cells open at their ends adjacent to said suction box section, an annular division plate in each -:of said cells, said annular division plates being located parallel 2 with the surface of said inner shell and extending from the open end of the cells adjacent to the suction box section to a point midway of their length to form separate drainage passages within the cells connecting the outer longitudinal half of the cells remote from the suction box section directly with said suction box, inner and. outer annular valve faces on the end of said cylinder defining the outer and inner. radial edges of the open ends of the cells, said suction box section being divided into vacuum and atmosphere compartments, a valve face on the inner end .of said suction box section facing against said inner and outer annular valve faces, and having arcuate ports in the suction box valve face and located radially in line With the openings of the said cylinder cells, said arcuate parts controlling the application of. vacuum and atmosphere pressure to said cells.

References Cited in the file of this patent UNITED STATES PATENTS' Germany Oct. 18 V 1913 

